Creating a New Level Set

I was hoping to copy and retexture the Desert Level Set, in order to create a new zone, complete with hub town and all that jazz.

Does anyone have a big-picture overview of the steps I'd need to take, aside from the actual texture work? Perhaps this is something best accomplished with an Alias?

As far as I can tell the paths to the texture a mesh uses are part of the Mesh file, and are NOT local? Is this the case? Is it possible to create a new alias without importing and re-exporting all the meshes from 3dsMAx or whatnot?